Eventually the strain of my guilt for hurting my ex ruined my new relationship and I ended things, though thie new girl may have had some personality disorder issues too, seeing me in very black or white terms.
That guilt will keep you in her pocket forever. You have nothing to feel guilty about. Breaking off a bad relationship and actually finding a NEW life for yourself is a GOOD thing, not a thing to feel guilty for. You just feel like you are leaving her behind... . and you are, but for the good because she's not going to go with you into better. And you are used to being manipulated by her tantrums and emotionalism.
She's pathological and will keep doing this to you. The up and down, the push/pull/push, the demand for attention, and the sexual garbage behind the scenes. She'll cast you off, or you'll leave, and then suddenly you're sucked back in again. And you might even kid yourself about "Nah... . I'm not that sucked in." Whatever . That was and is my ex wife. The quality of the remainder of your life literally depends on your ability to emotionally detach from her and her garbage, to stop taking the blame and guilt for things that you DO NOT need to feel guilty for, and to stop letting her lead you around like a puppy dog with her emotionalism and manipulation.
I was told 10 years ago, "She's pathological. She's going to keep doing this to you." The man who told me that was 100% right. It was hell.
*You aren't going to get the validation and closure you seek from her, ever. If she is constantly keeping tabs on old relationships, doesn't that tell you something? She doesn't WANT you to have closure. She wants to be able to leave you and then suck you back in on her terms and her time, whenever she wants.
*You aren't going to get explanations from her that make sense, ever. She has reasons for what she does, and they feel real to her. But they aren't.
*If you keep seeking it or living under the delusion that you can be "just friends", she's going to keep pulling on all those strings to keep you around for whenever she wants. You have to decide what kind of life you want. If you don't, she'll make that decision for you, and it will suck.
That's the bottom line.